不同处理方法对氮化硼负载铁基催化剂费托合成性能的影响

采用等体积浸渍法制备了三种氮化硼(BN)负载的铁基催化剂,将其用于费托合成反应中;结合XRD、TEM、FT-IR和H2-TPR等表征手段,研究了催化剂的物相结构、形貌特征、还原性能以及F-T合成反应性能。结果表明,Cu助剂加入不会破坏载体BN的物相结构,而硼砂的加入会提高载体BN的结晶度; Cu助剂和硼砂加入对催化剂形貌的影响不明显,但都会使所制备的负载型铁基催化剂还原温度降低。在n(H2_)/n(CO)=2.0、340℃、2 MPa和GHSV=1500 h~(-1)的条件下,三种催化剂Fe/BN、Fe/BNM和Fe-Cu/BN上的CO的转化率分别为12.3%、36.2%和31.6%,产物中甲烷选择性为57.9%、26.8%和44.7%。Fe-Cu/BN和Fe/BNM两种催化剂活性均比Fe/BN催化剂有所提高,表明BN负载的铁基催化剂可以通过加入助剂以及改善载体与活性组分之间的相互作用来提升其对F-T合成反应的催化活性。相关结果可为探索制备高活性的氮化硼基FT合成催化剂提供思路。

Effect of treatment method on the performance of boron nitride supported iron catalysts in the Fischer-Tropsch synthesis

Three boron nitride (BN) supported iron catalysts were prepared by the incipient-wetness impregnation method and characterized by XRD, TEM, FT-IR, and H₂-TPR; their phase structure, morphology, reduction behavior and performance in the F-T synthesis were investigated. The results indicate that the addition of Cu promoter has little influence on the phase structure of BN support, whereas the addition of sodium borate can improve the crystallinity of BN support. Although the change in the catalyst morphology by introducing Cu and sodium borate is very small, the addition of Cu and sodium borate can decrease the reduction temperature of the BN-supported iron-based catalysts. For F-T synthesis under 340℃, 2 MPa, GHSV=1500 h^-1 and n(H₂)/n(CO)=2, the conversions of CO over Fe/BN, Fe/BNM and Fe-Cu/BN are 12.3%, 36.2% and 31.6%, respectively and the corresponding selectivities to CH₄ are 57.9%, 26.8% and 44.7%, respectively. Fe-Cu/BN and Fe/BNM exhibit higher activity than Fe/BN, suggesting that adding promoter and improving the interaction between support and active component can both enhance the activity of boron nitride supported iron catalysts in F-T synthesis, which may give a clue to the design of highly active BN-supported iron catalysts.